1. Field of the Invention
The present disclosure relates, in general, to a chimera internal ribosomal entry site (IRES) sequence and uses thereof. More particularly, the present disclosure is directed to an improved baculovirus vector comprising the chimera IRES sequence for expressing genes in a mammalian or an insect host cell.
2. Description of Related Art
IRES sequences were first discovered in poliovirus RNA and encephalomyocarditis virus RNA, respectively. They are described as distinct regions of RNA molecules that are able to attract the eukaryotic ribosome to the mRNA molecule and, therefore, allow translation initiation to occur. This process is known as the internal initiation of translation.
It is common that IRESes are located at the 5′-untranslated region (5′UTR) of some RNA viruses such as small RNA viruses or hepatitis C viruses and allow translation of the RNAs in a cap-independent manner. When an IRES segment is placed between two reporter open reading frames (ORFs) in an eukaryotic mRNA molecule, it can drive translation of the downstream protein coding region independently of the 5′-cap structure bound to the 5′-end of the mRNA molecule. In such setup, both proteins are produced in the host cell.
In this study, a chimera IRES sequence was produced, and an improved baculovirus vector comprising the chimera IRES sequence for expressing genes in mammalian or insect host cells was disclosed.